A visit to a doctor's office, a clinic or a hospital may necessitate vascular access that is, the insertion of a needle or catheter into a patient's vein or artery. These procedures may be required for many reasons including: to administer fluids, drugs or solutions, to obtain and monitor vital signs, to place long-term access devices, and to perform simple venipunctures. Vascular access ranks as the most commonly performed invasive medical procedure in the U.S.—over 1.4 billion procedures annually—as well as the top patient complaint among clinical procedures. The overwhelming majority of vascular access procedures is performed without the aid of any visualization device and relies on what is observed through the patient's skin and by the clinician's ability to feel the vessel—basically educated guesswork.
Medical literature reports the following statistics: 28% first attempt IV failure rate in normal adults, 44% first attempt IV failure in pediatrics, 43% of pediatric IVs require three or more insertion attempts, 23% to 28% incidence of extravasations/infiltration, 12% outright failure rate in cancer patients, 25% of hospital in-patients beyond three days encounter difficult access. The miniature vein enhancer of the present invention may be used by a practitioner to locate a vein and is particularly useful when trying to locate a vein in the very old, very young or obese patients. More than fifty percent of attempts to find a vein in the elderly, who have a generally high percentage of loose, fatty tissue, and in children, who have a generally high percentage of small veins and “puppy fat”, are unsuccessful. The present invention is aimed at reducing and/or preventing the discomfort and delay associated with botched attempts to pierce veins for injections and blood tests. In addition, the present invention can cut the time it takes to set up potentially life-saving intravenous drip. During venous penetration, whether for an injection or drip, it is essential to stick a vein in exactly the right location. If a practitioner is only slightly off center, the needle will more than likely just roll off and require a re-stick.
Other Approaches
It is known in the art to use an apparatus to enhance the visual appearance of the veins in a patient to facilitate insertion of needles into the veins. An example of such a system is described in U.S. Pat. Nos. 5,969,754 and 6,556,858 incorporated herein by reference as well as a publication entitled “The Clinical Evaluation of Vein Contrast Enhancement”. Luminetx is currently marketing such a device under the name “Veinviewer Imaging System.”
The Luminetx Vein Contrast Enhancer (hereinafter referred to as LVCE) utilizes an infrared light source (generated by an array of LEDs) for flooding the region to be enhanced with infrared light. A CCD imager is then used to capture an image of the infrared light reflected off the patient. The resulting captured image is then projected by a visible light projector onto the patient in a position closely aligned with the image capture system. Given that the CCD imager and the image projector are both two dimensional, and do not occupy the same point in space, it is relatively difficult to design and build a system that closely aligns the captured image and the projected image.
A further characteristic of the LVCE is that both the imaging CCD and the projector have fixed focal lengths. Accordingly, the patient must be at a relatively fixed distance relative to the LVCE. This necessitates that the LVCE be positioned at a fixed distance from the region of the patient to be enhanced.
The combination of the size of the LVCE and the fixed focal arrangement precludes using the LVCE as small portable units that are hand held.
Other patents such as U.S. Pat. No. 6,230,046, issued to Crane et al., implement a light source for illuminating or trans-illuminating the corresponding portion of the body with light of selected wavelengths and a low-level light detector such as an image intensifier tube (including night vision goggles), a photomultiplier tube, photodiode or charge coupled device, for generating an image of the illuminated body portion, and optical filter(s) of selected spectral transmittance which can be located at the light source(s), detector, or both.
All citied references are incorporated herein by reference in their entireties. Citation of any reference is not an admission regarding any determination as to its availability as prior art to the claimed invention.
Objects of the Invention
The present invention is directed to technologies and processes associated with the use of one or more moving laser light sources to detect the presence of blood-filled structures, such as venous or arterial structures, below the surface of the skin and to project an image back on to the skin that shows the operator the pattern of detected structures. The present approach uses one or more laser light sources that are scanned over the body using mirrors and a light detector that measures the reflections of the laser light and uses the pattern of reflections to identify the targeted blood rich structures. Various preferred approaches are described for the main subsystems of the design as well as various alternative techniques for accomplishing the objects of this invention.